Patent GB-877110-A (GB)
Title: Improvements in or relating to devices for driving rotating workpieces in machine tools
IPC: B23B33/00
Filed: 1958-01-31
Abstract: 877,110. Chucks; drivers &c. LINDNER, W. Jan. 31, 1958 [Feb. 4, 1957], No. 3245/58. Class 83 (3). A device for driving work 1, Fig. 1, held between centres 2, 3 comprises a rotatable ring 5. This bears in an eccentric bore 51 in a housing 10 fixed to the machine-spindle 4 and has an eccentric, conical bore through which centre 3 extends to engage a conical hole 11 in the work. An eccentric conical or cylindrical driving projection 53 on ring 5 enters a counterbore 12 in the work when the ring is turned so that the axis of the projection coincides with that of the work. A leaf &c. spring 6 on the ring bears on the work and may be released by an electromagnet (Fig. 22, not shown). Upon rotation of spindle 4 and housing 10, slip occurs until projection 53 contacts counterbore 12. In a modification, Fig. 3, an eccentric, conical part E of the driving centre engages a bore 51, 52 in part of the ring 5, the concentric point of the centre passing through the rest of the ring into hole 11. A conical driving surface 53 on the ring drivingly engages the conical counterbore 12. A spring may be provided, as in Fig. 1. In a two-ring construction, Fig. 4, the housing 10, 10<SP>1</SP> bears in a part-spherical housing 9 on the spindle so that frictional drive-pads 7, 7<SP>1</SP> may bear evenly on the work 1. Bearings 151, 152 support the outer ring 5 in part 10 to which it is connected by a spring 8. A spring 8<SP>1</SP> connects inner ring 51 to part 10<SP>1</SP> on which it is mounted on bearings 151<SP>1</SP>, 152<SP>1</SP>. Part of the upper part of ring 5 and the lower part of ring 5<SP>1</SP> are cut away opposite the parts of the rings supporting the pads adjustably in holes 17, 17<SP>1</SP>. Axis SSa of ring 5 is eccentric to that (SS<SP>1</SP>) of the spindle 4 and to the axis SSi of ring 51. Instead of flange 9 being part-spherical, an intermediate partspherical part may be included between a perpendicular flange 9 and part 10. In a modified two-ring construction having opposed, pivoted V-shaped drivers 63, 631 for engaging the outer surface of the work, Fig. 6, driver 63 is pivoted on ring 5<SP>1</SP> and driver 63<SP>1</SP> on ring 5. Ring 5 is in an eccentric bearing 151 in an eccentric 13 adjustable for work of different sizes by a worm-gear 15, 16, the worm-wheel 15 of which supports a slide 62 guided in a slot 14 in eccentric 13 and a slide 621 in a guide-slot 141 in an eccentric 13<SP>1</SP> supporting ring 5<SP>1</SP> on an eccentric bearing 151<SP>1</SP>. The eccentricity of bearing 151 is equal but opposite to that of bearing 1511. Rings 5, 5<SP>1</SP> are interconnected by a ring 70 having bolts 59 supporting slides 60 engaging respectively in slots in rings 5, 5<SP>1</SP>. As in the construction of Fig. 4, springs may bias rings 5, 5<SP>1</SP>. Fig. 11 depicts a three-ring construction in which pads 153-153<SP>11</SP> on the rings 5, 51, 51<SP>1</SP> drivingly engage the bore of work 1. Bearings 151-151<SP>11</SP>, the eccentricities of which are equal but at 120 degrees to each other, support the rings in housing 10, and a ring 70 connected to each of rings 5-5<SP>11</SP> by a slide block (as in Fig. 6) is rotated to expand pads 153-153<SP>11</SP> into driving engagement with the work, by contact between the work and a leaf-spring 6 carried by ring 70. In a threering construction for drivingly engaging the outside surface of work 1, Fig. 13, the eccentricity of bearings 151<SP>1</SP>, 151<SP>11</SP> for rings 51, 5<SP>11</SP> is equal but opposite to that of bearing 151 for ring 5. Pivoted work-engaging shoes may be carried by the rings 5-5<SP>11</SP>. In a further modification, Figs. 15 and 16, the rings 5, 5, 51, 5<SP>11</SP> expand a steel sleeve 10 against the bore of the work 1. Rings 5 on eccentric bearings 51 support a pivot 164 for an arm 163 having bearing cylinders 7 engaging cylinder 10. Rings 5<SP>1</SP>, 5<SP>11</SP> are on oppositely-directed eccentric bearings 51<SP>1</SP> and have a pivot 164<SP>1</SP> for arms 163<SP>11</SP> supporting cylinders 71. Springs 6, 61 on the rings engage cylinder 10, and relative rotation of the bearings and rings expands cylinders 7, 7<SP>1</SP> against cylinder 10. A construction with three cylinders 7 is described (Fig. 19, not shown) in which the eccentricity of the bearings supporting the odd cylinder is less than that of the bearings supporting jointly the remaining pair of cylinders.